Overview

Overview developments in failure frequencies

An extensive analysis of data covering the period 1970 to 2016 has lead to the following overview:

Period

Interval

Number of incidents

Total system exposure ·106 km·yr

Primary failure frequency per 1,000 km·yr

1970 – 2007

7th report, 38 years

1,173

3.15

0.372

1970 – 2010

8th report, 41 years

1,249

3.55

0.351

1970 – 2013

9th report, 44 years

1,309

3.98

0.329

1970 – 2016

10th report, 47 years

1,366

4.41

0.310

1977 - 2016

40 years

1,143

4.12

0.278

1987 - 2016

30 years

723

3.44

0.210

1997 - 2016

20 years

418

2.53

0.165

2007 - 2016

10 years

208

1.39

0.150

2012 - 2016

5 years

97

0.72

0.136

Conclusions

The EGIG database is a valuable source of information on European gas pipelines and pipeline incidents.

EGIG has maintained and expanded the European Gas pipeline incident database. Seventeen gas transmission system operators in Europe now collect incident data on 142,794 km of pipelines every year. The total exposure, which expresses the length of a pipeline and its period of operation, is 4.41 million km·yr.

In the EGIG database 1,366 pipeline incidents are recorded in the period from 1970-2016.

The history of incidents collected in the database gives reliable failure frequencies. The overall failure frequency over the period 1970-2016 is equal to 0.31 incidents per year per 1,000 km.

The five year moving average failure frequency in 2016, which represents the average failure frequency over the past 5 years, equals 0.134 per year per 1,000 km.

The five year moving average and overall failure frequency have reduced over the years, although it has tended to stabilise over recent years.

Incidents caused by external interference and ground movement are characterised by potentially severe consequences. This emphasises their importance to pipeline operators and authorities.

Corrosion as a primary cause has now the same frequency rate as external interference, although consequences are much less severe. Over the last ten years, external interference, corrosion, construction defects and ground movement, represent 28%, 25%, 18% and 15%, respectively of the pipeline incidents reported.